JP3157248U - Oval dimple golf ball - Google Patents

Abstract

An oval dimple golf ball is provided. A plurality of dimples 2 having an elliptical peripheral edge having a major axis 1.2 times or more the minor axis and a depth at which turbulent flow is generated at the peripheral edge are formed on the surface of the sphere. To do. The elliptical dimple is formed such that when the sphere is assumed to be a triangular polyhedron, the major axis of the ellipse is positioned on each ridge line when the sphere is divided. A golf ball that flies while spinning spins as a result of the vortex formed at the peripheral edge of the elliptical dimple flowing along the peripheral edge of the elliptical dimple. Therefore, it is possible to obtain a flight distance longer than that of the circular dimple at the same initial speed. [Selection] Figure 1

Description

  The present invention relates to a golf ball having an oval dimple provided to increase the flight distance of the golf ball.

  Conventionally, a golf ball flies while rotating at a speed of 20 to 70 m / sec. Therefore, a golf ball having a dimple having a circular peripheral edge (hereinafter simply referred to as a circle) has a drag rather than a golf ball having no dimple in this speed region. It is widely recognized that long and long flight distances can be obtained if they are small and given the same initial velocity. It is also widely known that a large circular dimple is preferable at a low speed and a small circular dimple is preferable at a high speed.

  In recent years, various dimple shapes and cross-sectional shapes of dimples have been studied in consideration of increasing the lift-drag ratio (lift / drag) that affects the flight distance of golf balls. For example, the surface shape of the dimples is triangular and distributed at predetermined intervals, and the inverted triangular pyramid shape is used (Patent Document 1). The surface shape of the dimples is triangular and distributed at predetermined intervals. In addition, a cross-sectional shape having an inverted conical shape (Patent Document 2), and a dimple having a polygonal surface shape and forming a ridge shape at the boundary between adjacent dimples (Patent Document 3) have been proposed.

  That is, in the conventional golf ball, in order to increase the lift-drag ratio (lift / drag), dimples are indispensable anyway, and if necessary, a predetermined plane or ridge portion is provided between adjacent dimples. The idea that it was necessary was dominant.

U.S. Pat. No. 4,830,378 Japanese Patent Application Laid-Open No. 06-190082 JP 2005-185341 A

  However, the formation of circular dimples on the surface of a golf ball is necessary to increase lift and reduce drag, but the inventors' knowledge is that circular dimples on the surface of a conventional golf ball for a ball that flies while rotating On the contrary, it was found that the drag increases as the amount of spin generated there increases.

  Therefore, an object of the present invention is to provide a golf ball in which the lift-drag ratio (lift / drag) can be increased even when the spin rate is increased.

  As a result of intensive studies to solve the above problems, the present inventors have found that conventional ideas are not necessarily correct from aerodynamic experiments and discussions. That is, a golf ball flying while rotating has a separation point near its maximum diameter, and drag is generated by the vortex generated behind the golf ball from the separation point, and is greatly affected by the separation width. Therefore, conventionally, the formation of circular dimples moves the separation position of this vortex further, reduces the separation width and reduces the drag, and attempts to obtain lift by the difference in the air flow velocity between the upper and lower sides of the golf ball due to the dimples. Therefore, it is thought that formation of circular dimples is essential. However, vortices in the dimples are unavoidable between the golf ball that flies while rotating and the surrounding air, but if dimples are not formed, lift cannot be obtained, and a sufficient flight distance cannot be obtained. It was issued.

  The present invention has been made on the basis of the above knowledge. Although the dimple is formed, the peripheral edge having a major axis that is 1.2 times or more the minor axis of the dimple is an ellipse, and the peripheral edge is irregular. When an elliptical dimple has a depth that generates a flow, unlike a circular dimple, the vortex formed at the peripheral edge of the dimple is formed with a time difference, and the generated vortex flows along the peripheral edge of the elliptical dimple. It has been found that even if the spin rate increases while receiving lift from the dimples, the drag is not increased and the flight distance is improved by 5% or more even at the same initial speed.

  In the present invention, a plurality of dimples having an elliptical peripheral edge having a major axis that is 1.2 times or more, more preferably 2 to 5 times the minor axis, are formed on the surface of a pseudosphere composed of a sphere or a polyhedron. An elliptical dimple golf ball characterized by comprising: Here, the depth of the elliptical dimple is required to generate a turbulent flow, and is usually formed in the range of 0.2 to 0.5 mm. In the present invention, the oval shape has a long axis that is 1.2 times longer than the short axis, and is a shape in which the turbulent flow formed at the peripheral edge by the spin of the ball easily flows along the peripheral edge. It is distinguished from a circle and includes various geometrical ellipses, deformed ellipses, and the like.

  The elliptical dimples in the present invention are preferably formed uniformly on the entire ball surface, and the elliptical long axis is positioned on each ridge line when the sphere is virtually divided from a triangular polyhedron. It is preferable to form dimples. In a triangular polyhedron, 80 or more and 320 or so are preferred.

  Depending on the shape of the elliptical dimple, a circular dimple may be formed instead of the elliptical shape in order to improve the lift.

  In the conventional circular dimple, the vortex formed at the peripheral edge tends to stay, but according to the present invention, the vortex formed at the peripheral edge of the dimple is formed with a time difference by configuring the dimple on the ball surface in an elliptical shape. As a result, it does not flow and stay along the peripheral edge of the ellipse. Therefore, even if the spin rate is increased as compared with a golf ball having circular dimples, the drag is not increased, resulting in an improved flight distance.

1 is a perspective view showing an entire golf ball according to a first embodiment of the present invention. It is a perspective view which shows 2nd Embodiment. It is a perspective view which shows 3rd Embodiment. It is a schematic diagram of 2nd Embodiment. It is the sectional view on the AA line of FIG. FIG. 5 is a sectional view taken along line B-B in FIG. 4.

  Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. FIG. 1 shows a stereolithographic photograph of a golf ball according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a golf ball having a sphere having a diameter of approximately 43 mm, and an elliptical dimple 2 having a major axis 3.7 times longer than a minor axis is formed along a ridge formed by a triangular virtual 180-hedron. The dimple depth is 0.3 mm.

  FIG. 2 is a stereolithographic photograph of a golf ball 11 that forms a sphere, and forms a major axis that is 1.9 times the minor axis, that is, approximately twice as long as the minor axis, along a ridge formed by a triangular virtual 180-hedron. An elliptical dimple 12 having a depth of 0.3 mm is formed. 4 is a schematic diagram of FIG. 2, FIG. 5 is an enlarged sectional view taken along line AA of FIG. 4, and FIG. 6 is an enlarged sectional view taken along line BB of FIG.

  FIG. 3 is a stereolithographic photograph of a golf ball 21 that forms a sphere. A long axis of 4.0 times the short axis is formed along a ridge formed by a triangular virtual 320-hedron, and the depth is 0.3 mm. An elliptical dimple 22 is formed.

  The gist of the present invention is that the peripheral edge of the dimple is elliptical, turbulent flow is generated at the peripheral edge with a time difference, and the formed vortex flows along the elliptical peripheral edge. Variations and modifications can be made without departing from the spirit of the invention.

1,11,21 spherical golf ball 2,12,22 oval dimple

Claims (1)

  When a sphere is assumed to be a triangular polyhedron on the sphere surface of a golf ball, an elliptical dimple is formed so that the major axis is along each ridgeline, and the elliptical dimple has a major axis that is 1.2 times or more the minor axis. An elliptical dimple golf characterized in that it is surrounded by an elliptical peripheral edge and the depth of the elliptical dimple is a depth required to generate turbulent flow and is in the range of 0.2 to 0.5 mm ball.